This invention relates to a two-cycle engine for an outboard motor and more particularly to an improved supercharger and drive arrangement for an internal combustion engine.
The use of superchargers to improve the performance of internal combustion engines is well known. Superchargers have particular utility with two-cycle internal combustion engines because they can not only improve the performance of the engine but also improve the scavenging of the engine. Superchargers have particular utility in outboard motors because of the power increase which they can obtain and this has considerable advantage in permitting a compact, high power outboard motor. However, because of the compactness required for outboard motors, the placement and drive arrangement for a supercharger can be particularly critical, particularly with this type of application.
The supercharger should be basically positioned relatively close to the crankshaft of the engine, from which it is driven In some types of applications, this is accomplished by placing the supercharger is a generally aligned relationship with the crankshaft so that it can be driven nearly directly off end the crankshaft and the supercharger extends beyond the front of the engine. However, when mounted in an outboard motor, this gives rise to considerable height of the engine and at the power head and this is not at all desirable.
It is, therefore, a principal object of this invention to provide an improved supercharger and drive arrangement for an internal combustion engine and particularly one which may be utilized in conjunction with an outboard motor.
It is a further object to this invention to provide an improved and compact supercharger, internal combustion engine arrangement.
In outboard motor applications, it is desirable to maintain a low center of gravity of the outboard motor. In addition, the outboard motor is frequently tilted up about a horizontally disposed axis and it is desirable to maintain the center of gravity as far forward as possible so as to assist in this tilting up operation.
It is, therefore, a still further object to this invention to provide an improved supercharger drive arrangement for an outboard motor wherein the supercharger can be positioned at the front of the outboard motor and will not extend vertically above the engine.